Ni-RuO x Modified catalytic materials and their preparation methods, OER catalytic applications and water electrolysis devices

Abstract

This invention belongs to the field of electrocatalytic materials and water electrolysis for hydrogen production, and discloses a Ni-RuO x Modified catalytic materials and their preparation methods, OER catalytic applications, and water electrolysis devices are disclosed. The preparation method of the catalytic material involves treating a mixture containing a ruthenium source, a nickel source, and potassium bromide with oxygen plasma to obtain a modified Ni-RuO2 precursor. The oxygen plasma treatment process is carried out at a temperature of 150-200℃ and a power of 100-150 W. The modified Ni-RuO2 precursor is then thermally annealed under a protective atmosphere at a temperature of 200-300℃ to obtain the Ni-RuO2 precursor. x Modified catalytic materials. This invention demonstrates that the preparation method described herein can achieve in-situ uniform doping of nickel in the RuO2 lattice, precise control of oxygen vacancies, and directional construction of discrete nanoparticles. This invention also demonstrates that the preparation method can significantly improve the OER performance of the prepared materials.

Description

Technical Field

[0001] This invention belongs to the field of water electrolysis for hydrogen production technology, and specifically relates to a water electrolysis catalytic material. Background Technology

[0002] With the advancement of global "dual-carbon" goals, green hydrogen, as a zero-carbon energy carrier, has attracted much attention. Proton exchange membrane (PEM) water electrolysis technology has become a core technological path for the large-scale production of green hydrogen due to its advantages such as fast start-up speed, high gas purity, and adaptability to fluctuating renewable energy sources. The anodic reaction of PEM water electrolysis is the oxygen evolution reaction (OER) under acidic conditions. This reaction involves a four-electron transfer process, which is kineticly slow and requires a highly efficient catalyst to reduce the overpotential.

[0003] Ruthenium dioxide (RuO2) is widely considered one of the most promising acidic OER catalysts due to its excellent electrical conductivity, moderate oxygen binding energy, and good chemical stability. However, pure-phase RuO2 still faces the following challenges in practical applications:

[0004] 1. Insufficient active sites: Traditional RuO2 has a limited specific surface area and low density of active sites;

[0005] 2. Stability Challenge: Under acidic high potential, Ru is easily oxidized to soluble RuO4, leading to continuous dissolution of the catalyst;

[0006] 3. Intrinsic activity is limited: The electronic structure of pure phase RuO2 is not optimal, and there is still room for improvement in OER kinetics.

[0007] To address the aforementioned issues, existing technologies often employ elemental doping or morphology control strategies. For example, patent document CN119121297A discloses a template method for preparing ultrafine nickel-doped ruthenium oxide electrolytic water production catalysts and their applications. The catalyst comprises RuO2 matrix and nickel element uniformly doped into the matrix, with the nickel element accounting for 5% to 20% of the total catalyst mass. Another example is patent document CN120119266A, which discloses a method for preparing a ruthenium oxide-doped molybdenum oxide / nickel hydroxide all-pH electrolytic water catalyst. This method includes the following steps: first, mixing molybdenum salt with an aqueous solution of sodium dodecylbenzenesulfonate and then placing it into a nickel foam substrate; subsequently, a hydrothermal reaction is carried out, followed by calcination in a reducing atmosphere.

[0008] In summary, existing technologies for elemental doping involve introducing transition metals to adjust the Ru-O bond strength, but these methods often involve simple mixing followed by calcination. The dopant elements tend to accumulate on the surface rather than being in-situ doped, resulting in limited optimization of the electronic structure. Regarding morphology control, template methods and hydrothermal methods are used to construct porous structures, but these suffer from difficulties in template removal, cumbersome processes, and poor pore connectivity. Furthermore, achieving synergistic construction of doping modification and porous structures is challenging. While molten salt methods, as efficient material synthesis methods, provide a high-temperature liquid phase environment to promote atomic diffusion, current methods for preparing RuO2-based catalysts primarily utilize the molten salt medium function, failing to achieve the multiple effects of crystal form control, morphology induction, and synergistic doping. Moreover, the subsequent washing process is often crude, easily leading to pore structure collapse or soluble salt residue, affecting catalyst performance.

[0009] Furthermore, existing performance evaluations of RuO2-based catalysts mostly focus on overpotential and simple time decay rate, lacking key quantitative indicators such as crystal phase purity, metal dissolution rate, and pore volume. Moreover, the application parameters in proton exchange membrane water electrolysis devices are not clearly defined, leading to a disconnect between laboratory preparation and industrial application. Therefore, developing a simple, scalable RuO2-based catalyst preparation method that synergistically achieves in-situ nickel lattice doping and the directional construction of a through-hole porous structure, while simultaneously clarifying its key parameters for industrial application, has become a core requirement for overcoming the bottleneck in anode catalysis for proton exchange membrane water electrolysis. Summary of the Invention

[0010] To address the problems of existing RuO2-based catalysts, such as easy particle agglomeration and cross-linking, low utilization of active sites, uneven distribution of doping elements, high Ru dissolution rate under acidic conditions, dependence on high-temperature molten salts in the preparation process, difficulty in template removal, and unclear parameters for industrial applications, this invention provides a Ni-RuO2 catalyst. x The preparation method of modified catalytic materials aims to prepare a catalytic material with excellent catalytic activity.

[0011] The second objective of this invention is to provide Ni-RuO prepared by the aforementioned method. x Modified catalytic materials and their application in OER catalysis.

[0012] A third objective of this invention is to provide a product comprising the Ni-RuO x Water electrolysis devices using modified catalytic materials.

[0013] A Ni-RuO x The method for preparing modified catalytic materials involves treating a mixture containing a ruthenium source, a nickel source, and potassium bromide with oxygen plasma to obtain a modified Ni-RuO2 precursor; the temperature during the oxygen plasma treatment is 150~200℃, and the power is 100~150 W.

[0014] The modified Ni-RuO2 precursor was thermally annealed at 200-300°C under a protective atmosphere to obtain the Ni-RuO2 precursor. x Modified catalytic materials.

[0015] This invention innovatively employs oxygen plasma treatment with ruthenium and nickel sources under KBr assistance, further combined with low-temperature thermal annealing. This synergistic effect optimizes the doping behavior and discrete distribution of nickel, as well as the vacancy structure. Research indicates that the described preparation method enables in-situ uniform doping of nickel in the RuO2 lattice, precise control of oxygen vacancies, and directional construction of discrete nanoparticles. Further research demonstrates that the described preparation method significantly improves the OER performance of the prepared material. Compared to existing RuO2-based catalysts, the Ni-RuO2 catalyst prepared in this invention exhibits superior performance. x The material is used at lower Ru loading (e.g., 20~50 μg Ru / cm). 2 An overpotential of 213 mV can be achieved at these conditions (0.5 M H2SO4, 10 mA / cm). 2 It remained relatively stable during 100 h of acidic OER operation, demonstrating good activity and stability advantages. Furthermore, the preparation process did not exceed 300℃, requiring no high-temperature molten salt or template, making the process relatively simple.

[0016] In this invention, the ruthenium source includes at least one of ruthenium trichloride, ruthenium trichloride hydrate, ruthenic acid, and ruthenic acid salt.

[0017] The nickel source includes at least one of nickel acetylacetone, nickel nitrate, nickel chloride, and nickel acetate.

[0018] The mass ratio of ruthenium source, nickel source and potassium bromide is 5~15:1:40~100; it can be further 8~12:1:50~80.

[0019] In this invention, the mixture is obtained by solid-phase mixing of ruthenium source, nickel source and potassium bromide; or, the mixture is obtained by liquid-phase mixing of ruthenium source, nickel source and potassium bromide in a solvent and then removing the solvent.

[0020] In this invention, the atmosphere during the oxygen plasma treatment process is a mixture of oxygen and protective gas, wherein the protective gas includes at least one of nitrogen and rare gases.

[0021] In the gas mixture, the volume ratio of oxygen to protective gas is 1:1 to 10; preferably 1:4 to 6.

[0022] The mixed gas flow rate during the oxygen plasma treatment process is 50~80 mL / min;

[0023] The oxygen plasma treatment time is 30~60 min.

[0024] Preferably, the oxygen plasma treatment can be performed using a pulsed plasma mode (duty cycle 30%~70%, frequency 100~300 Hz), or a rotating plasma reactor can be used to dynamically irradiate the powder, or the plasma mixture can also contain 1~5 vol% water vapor.

[0025] Studies have shown that under optimized plasma treatment schemes, the physicochemical structure of materials can be further optimized, which helps to further enhance the OER activity and stability of materials.

[0026] In this invention, the protective atmosphere during the thermal annealing process includes at least one of nitrogen and rare gases; the annealing temperature is preferably 240~300℃; more preferably 250~290℃.

[0027] The annealing time is 1~3 hours;

[0028] After annealing, cooling, washing with water, and drying, the Ni-RuO was obtained. x Modified catalytic materials.

[0029] Preferably, before annealing, a pre-annealing process is included, wherein the pre-annealing temperature is 150~200℃ and the pre-annealing time is 0.5~1.5 h. For example, in a preferred embodiment of the present invention, the thermal annealing can be carried out by staged heating: first holding at 150~200℃ for 0.5~1.5 h, and then raising the temperature to 240~300℃; preferably, holding at 250~290℃ for 1~2 h. The preferred gradient annealing treatment can further enhance the OER activity and stability of the prepared material.

[0030] Preferably, annealing is followed by rapid cooling; wherein the cooling rate is ≥50℃ / min. This preferred gradient annealing treatment can further enhance the OER activity and stability of the prepared material.

[0031] Preferably, acid treatment is performed after annealing; the acid treatment solution is an aqueous solution. For example, the product after annealing and cooling can be washed sequentially with deionized water, 0.005~0.02 M dilute sulfuric acid or dilute nitric acid, and then washed with deionized water until neutral.

[0032] Preferably, the annealing atmosphere also contains 0.1 to 1 vol% oxygen or 0.5 to 2 vol% ammonia.

[0033] The present invention also provides a Ni-RuO prepared by the preparation method described above. x Modified catalytic materials.

[0034] The preparation method described in this invention can endow the material with special physicochemical properties. For example, the prepared catalyst is a pure rutile phase composed of highly crystalline cubic / irregular discrete nanoparticles of 5-20 nm, with no cross-linked porous network structure. Ni element is uniformly doped in the crystal lattice with a controllable doping amount of 1-5 wt%, oxygen vacancy concentration of 3.0-5.5 at%, surface Br⁻ residue ≤1.0 wt%, and specific surface area ≥92 m². 2 / g, particle dispersion ≥91%.

[0035] The present invention also provides a Ni-RuO prepared by the preparation method described above. x The modified catalytic material is used as a catalyst for the OER reaction.

[0036] This invention can utilize known OER catalysis principles and operations to produce the Ni-RuO described in this invention. x Modified catalytic materials are used as catalysts for catalyzing OER reactions.

[0037] The application described in this invention is preferably used as a catalyst for catalyzing the OER reaction in an acidic solution; the acidic solute in the acidic solution includes at least one of sulfuric acid, perchloric acid, nitric acid, and methanesulfonic acid; the concentration of the acidic solute in the acidic solution is 0.1~1.0 M; more preferably 0.4~0.6 M.

[0038] The present invention also provides a water electrolysis device comprising Ni-RuO prepared by the aforementioned method. x Modified catalytic materials, or through Ni-RuO x Modified catalytic materials were prepared.

[0039] The water electrolysis device of the present invention, in addition to containing the Ni-RuO of the present invention, x Apart from the modified catalytic material, the other components and structural relationships can all be known.

[0040] Beneficial effects

[0041] 1. The low-temperature synergistic process of "passivation-oxidation-annealing" breaks the dependence on high-temperature molten salt.

[0042] This invention couples three steps—bromine ion surface passivation, low-temperature oxidation with oxygen plasma (150~200℃), and low-temperature thermal annealing in an Ar atmosphere (≤300℃)—into a single system. KBr is not a traditional high-temperature molten salt medium (reaction temperature much lower than its melting point of 734℃), but rather acts as a "low-temperature bromide ion modifier": Br -Adsorbed onto the particle surface in plasma, it simultaneously inhibits agglomeration (dispersion ≥91%) and guides oxygen vacancy nucleation; subsequent annealing precisely locks the oxygen vacancy concentration at 3.0~5.5 at%. This three-step synergistic approach achieves the three goals of "high dispersion, uniform doping, and controllable oxygen vacancies" that would normally require multiple steps, and cannot be derived by using KBr alone, plasma alone, or annealing alone.

[0043] 2. The synergistic effect of opposite electronic components overcomes the contradiction between activity and stability.

[0044] XPS and ICP-MS confirmed that KBr increases the electron density of Ru and reduces Ru–O covalentity (inhibiting Ru over-oxidation), while Ni slightly increases the oxidation state of Ru (enhancing intrinsic activity). Despite their opposing electronic effects, they unexpectedly synergistically interact within the same system—Ru dissolution decreases to 0.011 mg / L (1 / 8 of commercial RuO2), while the overpotential is only 213 mV. This effect of "opposite-directed co-promotion" cannot be expected from single doping or single-surface passivation.

[0045] 3. Regulation of the "inhibition-moderate activation" pathway to precisely control the participation of lattice oxygen.

[0046] DEMS showed that AEM was dominant in all samples. Ni doping alone weakly activated LOM (Laminated Omni). 34 O2 increased slightly, but the presence of KBr further suppressed the already weak LOM ( 34 (O2 decrease). The combination of these two factors results in nonlinear path optimization: KBr-dominated suppression and Ni-moderate activation suppress lattice oxygen participation below a safe threshold, avoiding lattice oxygen loss and Ru dissolution caused by LOM. This regulatory mode cannot be achieved in a single-component system.

[0047] 4. Clean structure lock-in that is "removable after use"

[0048] KBr acts as both a nucleation site and an ion diffusion channel in the reaction (solid-state ion conduction at 450℃). It can be completely removed by washing with water / dilute acid after the reaction (no K / Br signal is detected in XPS), but the Ni doping and discrete structure are "locked" in the pure RuO2 lattice. This utilizes the auxiliary function of KBr while avoiding impurity residue. This "dynamic assistance-static locking" mechanism cannot be expected by simple addition and solves the pain points of traditional template methods (difficult to remove residue) and molten salt methods (requiring strong post-etching treatment). Attached Figure Description

[0049] Figure 1 The image shows a TEM image of the Ni-RuO2 catalyst prepared in Example 1, which consists of 5-20 nm cubic / irregular discrete nanoparticles without crosslinking or agglomeration.

[0050] Figure 2 The X-ray diffraction patterns are of the Ni-RuO2 prepared in Example 1 and the catalyst of the comparative example.

[0051] Figure 3 Comparison of OER polarization curves of the Ni-RuO2 catalyst prepared in Example 1 with those of the comparative example and commercial RuO2 in 0.5M H2SO4.

[0052] Figure 4 The Ni-RuO2 catalyst prepared in Example 1, compared with the comparative example and commercial RuO2 at 10 mA / cm 2 Timing potential stability curves under current density.

[0053] Figure 5 The fine 1s XPS spectra of Ni-VO-RuO2 prepared in Example 1 and O in the comparative example confirm the presence of oxygen vacancies (characteristic peak at 529.8 eV). Detailed Implementation

[0054] The present invention will be further described in detail below with reference to the embodiments, but the scope of protection of the present invention is not limited thereto.

[0055] Example 1: Preparation of Ni-VO-RuO2-1 catalyst

[0056] Step 1: Weigh 30 mg of ruthenium trichloride hydrate (RuCl3·3H2O), 3 mg of nickel acetylacetone (Ni(acac)2, with a mass ratio of ruthenium trichloride hydrate to nickel acetylacetone of 10:1), and 180 mg of potassium bromide (with a mass ratio of potassium bromide to ruthenium trichloride hydrate of 6:1). Place them in an agate mortar and mix them evenly. Add 90 μL of anhydrous ethanol to moisten the mixture, grind it thoroughly for 25 min until a uniform paste is formed, sonicate it at 120 W for 12 min, and vacuum dry it at 65 °C for 15 h to obtain the mixture.

[0057] Step 2: Spread the above mixture evenly in a quartz boat, place it in the plasma reaction chamber, seal it, and introduce an O2 / Ar mixed atmosphere (volume ratio 1:5, gas flow rate 60 mL / min). Heat it to 180℃ and perform plasma oxidation treatment at 130W power for 45 min to obtain the modified Ni-RuO2 precursor.

[0058] Step 3: Place the modified Ni-RuO2 precursor into a tube furnace, heat it to 280℃ at 5℃ / min under Ar atmosphere (flow rate 50mL / min), hold it at that temperature for 1.5 h, and allow it to cool naturally in the furnace. Then, wash it three times (6 min each time) by centrifugation with 28℃ deionized water at 9000 rpm, and dry it under vacuum at 65℃ for 14 h to obtain the Ni-V0-RuO2-1 catalyst.

[0059] Example 2

[0060] The only difference from Example 1 is the amount of nickel acetylacetone used; the experimental groups were as follows:

[0061] Group A: The amount of nickel acetylacetone used was 2.5 mg (mass ratio of ruthenium trichloride hydrate to nickel acetylacetone 12:1), and other operations and parameters were the same as in Example 1. The resulting product was denoted as Ni-VO-RuO2-2.

[0062] Group B: The amount of nickel acetylacetone was changed to 3.75 mg (mass ratio of ruthenium trichloride hydrate to nickel acetylacetone 8:1), and other operations and parameters were the same as in Example 1. The resulting product was denoted as Ni-VO-RuO2-3.

[0063] Example 3

[0064] The only difference from Example 1 is the amount of KBr used; the experimental groups were as follows:

[0065] Group A: The amount of KBr used was 150 mg (the mass ratio of potassium bromide to ruthenium trichloride hydrate was 5:1); other operations and parameters were the same as in Example 1. The resulting product was denoted as Ni-VO-RuO2-4;

[0066] Group B: The amount of KBr used was 240 mg (the mass ratio of potassium bromide to ruthenium trichloride hydrate was 8:1); other operations and parameters were the same as in Example 1. The resulting product was denoted as Ni-VO-RuO2-5.

[0067] Example 4

[0068] The only difference from Example 1 is that the parameters for step 2 are: a volume ratio of O2 / Ar mixed atmosphere of 1:6, a gas flow rate of 80 mL / min, a power of 120 W, and a processing time of 50 min. All other operations and parameters are the same as in Example 1. The resulting product is denoted as Ni-VO-RuO2-6.

[0069] Example 5

[0070] The only difference from Example 1 is that the plasma oxidation temperature in step 2 is changed to 160°C; all other operations and parameters are the same as in Example 1. The resulting product is denoted as Ni-VO-RuO2-7.

[0071] Example 6

[0072] The only difference from Example 1 is that the plasma oxidation temperature in step 2 is changed to 200°C; all other operations and parameters are the same as in Example 1. The resulting product is denoted as Ni-VO-RuO2-8.

[0073] Example 7: Changing the heat annealing temperature (250°C)

[0074] The only difference from Example 1 is that the heat annealing temperature in step 3 is changed to 250°C and the annealing time is 2.5 hours; all other operations and parameters are the same as in Example 1. The resulting product is denoted as Ni-VO-RuO2-9.

[0075] Example 8: Changing the heat annealing temperature (270°C)

[0076] The only difference from Example 1 is that the heat annealing temperature in step 3 is changed to 270°C; all other operations and parameters are the same as in Example 1. The resulting product is denoted as Ni-VO-RuO2-10.

[0077] Example 9: Changing the heat annealing temperature (290°C)

[0078] The only difference from Example 1 is that the heat annealing temperature in step 3 is changed to 290°C and the annealing time is 1 hour; all other operations and parameters are the same as in Example 1. The resulting product is denoted as Ni-VO-RuO2-11.

[0079] Example 10: Segmented Annealing

[0080] The only difference from Example 1 is that the hot annealing in step 3 uses segmented heating: first, the temperature is increased to 180°C at 5°C / min and held for 0.5 hours, then increased to 280°C at 5°C / min and held for 1.5 hours, followed by natural cooling. All other operations and parameters are the same as in Example 1. The resulting product is denoted as Ni-VO-RuO2-12.

[0081] Example 11: Rapid cooling treatment after annealing

[0082] The only difference from Example 1 is that after the thermal annealing in step 3, the quartz boat was quickly moved from the high-temperature zone of the tube furnace to the room-temperature zone (cooling rate of approximately 60°C / min), and the rest of the operation was the same. The resulting product was denoted as Ni-VO-RuO2-13.

[0083] Example 12: Washing with dilute acid after annealing

[0084] The only difference from Example 1 is that in step 3, the centrifugal washing is changed to: first, centrifuging and washing twice with deionized water at 28°C (9000 rpm, 6 min), then washing once with 0.01 M dilute sulfuric acid (9000 rpm, 6 min), and then washing once with deionized water (9000 rpm, 6 min). All other operations are the same. The resulting product is denoted as Ni-VO-RuO2-14.

[0085] Example 13: Pulsed Plasma Processing

[0086] The only difference from Example 1 is that in step 2, the oxygen plasma treatment uses a pulsed mode with a duty cycle of 50% and a frequency of 200Hz, while other parameters are the same as in Example 1. The resulting product is denoted as Ni-VO-RuO2-15.

[0087] Comparative Example 1

[0088] The only difference from Example 1 is that nickel acetylacetone is not added; all other operations and parameters are the same as in Example 1.

[0089] Comparative Example 2

[0090] The only difference from Example 1 is that KBr is not added, while all other operations and parameters are the same as in Example 1.

[0091] Comparative Example 3

[0092] Traditional synthesis method: Weigh 30 mg of ruthenium trichloride hydrate, 3 mg of nickel acetylacetonate, and 450 mg of KBr (KBr:Ru mass ratio 15:1), add 70 mL of alcohol-water mixed solvent (ethanol:water = 6:1), stir to dissolve at 50 °C, dry to constant weight at 80 °C, grind, calcine at 450 °C for 2 h, wash 4 times with hot deionized water at 60 °C, wash 3 times with anhydrous ethanol, and vacuum dry at 60 °C for 15 h. The obtained product has a cross-linked porous structure and is denoted as Ni-RuO2-molten.

[0093] Comparative Example 4

[0094] The only difference from Example 1 is that the annealing temperature in step 3 is changed to 350°C; all other operations and parameters are the same as in Example 1. The resulting product is denoted as Ni-VO-RuO2-350.

[0095] Comparative Example 5

[0096] The only difference from Example 1 is that in step 2, the plasma power is changed to 80 W, while the other operations and parameters are the same as in Example 1.

[0097] Comparative Example 6

[0098] The only difference from Example 1 is that KBr is replaced with an equimolar amount of NaBr; all other operations and parameters are the same as in Example 1. The resulting product is denoted as Ni-VO-RuO2-NaBr.

[0099] Comparative Example 7

[0100] The only difference from Example 1 is that KBr is replaced with an equimolar amount of KCl; all other operations and parameters are the same as in Example 1. The resulting product is denoted as Ni-VO-RuO2-KCl.

[0101] Comparative Example 8

[0102] The only difference from Example 1 is that nickel acetylacetone is replaced with an equimolar amount of cobalt acetylacetone; all other operations and parameters are the same as in Example 1. The resulting product is denoted as Co-VO-RuO2.

[0103] Comparative Example 9

[0104] The only difference from Example 1 is that the oxygen plasma treatment in step 2 is omitted, and the mixture obtained in step 1 is directly subjected to the thermal annealing in step 3. All other operations and parameters are the same as in Example 1. The resulting product is denoted as Ni-RuO2-noPlasma.

[0105] Electrochemical performance testing

[0106] Weigh 2 mg of the prepared catalyst and disperse it in a mixture of 150 μL ethanol, 90 μL distilled water, and 10 μL 5 wt% Nafion solution. Sonicate the mixture to obtain a uniformly dispersed slurry. Take a certain amount and uniformly drop-coat it onto the surface of a 5 mm glassy carbon electrode as the working electrode. The Ru loading is controlled at 20–50 μg Ru / cm³. 2 A 0.5 M sulfuric acid solution was selected as the electrolyte, and electrochemical data were measured using linear sweep voltammetry at a scan rate of 5 mV / s. Stability was tested using chronopotentiometric method at 10 mA / cm². 2 Continuous monitoring at current density.

[0107] The structure of each case is shown in Tables 1 and 3:

[0108]

[0109]

[0110]

[0111] The room temperature described in this invention is 25°C.

[0112] Results Analysis

[0113] 1. Overpotential is significantly reduced under high current density.

[0114] At 100 mA / cm 2 Under the given conditions, the overpotential of Example 1 was only 255 mV, which was far superior to that of Comparative Example 1 (350 mV), Comparative Example 2 (335 mV) and commercial RuO2 (340 mV), indicating that Ni doping and Br⁻ modification synergistically optimized the high-current catalytic performance of the material.

[0115] 2. Excellent performance stability under high temperature and acidic conditions.

[0116] At 60°C, Example 1 was tested at 10 mA / cm². 2The overpotential was only 220 mV, which was only 7 mV higher than that at room temperature, far superior to conventional RuO2-based catalysts, indicating that KBr modification can effectively suppress structural degradation and activity decay at high temperatures.

[0117] 3. Excellent long-term stability under acidic conditions

[0118] In Example 1, the potential increase was only +12 mV during the 200 h chronopotential test, which was significantly better than Comparative Example 1 (+70 mV), Comparative Example 2 (+45 mV) and commercial RuO2 (failed at 80 h), indicating that the material has excellent structural and compositional stability.

[0119] 4. Ru dissolution is at an extremely low level.

[0120] The Ru dissolution rate in Example 1 was only 0.011 mg / L after 100 h, which is much lower than that of the comparative samples such as Comparative Example 1 (0.045 mg / L) and Comparative Example 2 (0.025 mg / L), confirming that Br⁻ surface modification and Ni lattice doping can effectively suppress the dissolution and loss of Ru active components.

[0121] 5. KBr is irreplaceable.

[0122] After replacing KBr with KCl (Comparative Example 7), 100 mA / cm 2 The overpotential rose to 360 mV, and the potential increase reached +60 mV after 200 h, indicating a significant performance degradation, suggesting that K + With Br - The synergistic effect of [the material] is crucial to the material structure and properties, and Cl⁻ cannot achieve the same effect.

[0123] 6. Oxygen plasma treatment is a key step.

[0124] Without oxygen plasma treatment (Comparative Example 9), 10 mA / cm 2 The overpotential is as high as 360 mV and it fails after 120 h, indicating that oxygen plasma plays an irreplaceable role in low-temperature oxidation, surface activation and structure construction.

Claims

1. A Ni-RuO x The method for preparing modified catalytic materials is characterized by, A mixture containing ruthenium source, nickel source and potassium bromide was subjected to oxygen plasma treatment to obtain a modified Ni-RuO2 precursor; the temperature during the oxygen plasma treatment was 150~200℃ and the power was 100~150 W. The modified Ni-RuO2 precursor was thermally annealed at 200-300°C under a protective atmosphere to obtain the Ni-RuO2 precursor. x Modified catalytic materials.

2. The preparation method of the Ni-RuOx modified catalytic material as described in claim 1, characterized in that, The ruthenium source includes at least one of ruthenium trichloride, ruthenium trichloride hydrate, ruthenic acid, and ruthenate; the nickel source includes at least one of nickel acetylacetonate, nickel nitrate, nickel chloride, and nickel acetate. The mass ratio of ruthenium source, nickel source and potassium bromide is 5~15:1:40~100.

3. The Ni-RuO as described in claim 1 x The method for preparing modified catalytic materials is characterized by, The mixture is obtained by solid-phase mixing of ruthenium source, nickel source and potassium bromide; or by liquid-phase mixing of ruthenium source, nickel source and potassium bromide in a solvent followed by solvent removal to obtain the mixture.

4. The Ni-RuO as described in claim 1 x The method for preparing modified catalytic materials is characterized by, The atmosphere during the oxygen plasma treatment process is a mixture of oxygen and protective gas, wherein the protective gas includes at least one of nitrogen and rare gases. In the gas mixture, the volume ratio of oxygen to protective gas is 1:1 to 10; preferably 1:4 to 6. The flow rate of the mixed gas during the oxygen plasma treatment process is 50~80 mL / min; The processing time for the oxygen plasma treatment process is 30 to 60 minutes.

5. The Ni-RuO as described in claim 1 x The method for preparing modified catalytic materials is characterized by, The oxygen plasma treatment is performed in pulsed plasma mode; or using a rotary plasma reactor; or 1-5 vol% water vapor is added to the plasma mixture.

6. The method for preparing the Ni-RuOx modified catalytic material as described in claim 1, characterized in that, The protective atmosphere during the hot annealing process includes at least one of nitrogen and rare gases; The annealing temperature is 240~300℃; preferably 250~290℃. The annealing time is 1 to 3 hours.

7. The preparation method of the Ni-RuOx modified catalytic material as described in claim 6, characterized in that, Before annealing, a pre-annealing process is also included, wherein the pre-annealing temperature is 150~200℃ and the pre-annealing time is 0.5~1.5 h; Preferably, the annealing atmosphere also contains 0.1-1 vol% oxygen or 0.5-2 vol% ammonia. Preferably, the annealing is followed by a rapid cooling treatment; wherein the cooling rate of the rapid cooling is ≥50℃ / min. Preferably, acid treatment is performed after annealing; the acid solution for acid treatment is a 0.005~0.02 M dilute sulfuric acid or dilute nitric acid aqueous solution; After annealing, cooling, washing with water, and drying, the Ni-RuOx modified catalytic material is obtained.

8. A Ni-RuO prepared by the preparation method according to any one of claims 1 to 7 x Modified catalytic materials.

9. A Ni-RuO prepared by the preparation method according to any one of claims 1 to 7 x The application of modified catalytic materials is characterized by, It can be used as a catalyst to catalyze the OER reaction; Preferably, it is used as a catalyst to catalyze the OER reaction in an acidic solution; the acidic solute in the acidic solution includes at least one of sulfuric acid, perchloric acid, nitric acid, and methanesulfonic acid; the concentration of the acidic solute in the acidic solution is 0.1~1.0M.

10. A water electrolysis device, characterized in that, Ni-RuO prepared by the method according to any one of claims 1 to 7 x Modified catalytic materials, or through Ni-RuO x Modified catalytic materials were prepared.

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